1. Field of the Invention
The present invention relates to an apparatus for manufacturing an information carrier. More particularly, to a disk manufacturing apparatus in which a recording beam is irradiated on the surface of a master disk of optical disks for the purpose of recording of information, for use in a mastering process of producing a master disk of optical disks.
2. Description of Background Information
As an example of video or audio information recording system using a disk-shaped recording medium, there is an optical recording system for optically recording the information on a master disk of video disks. This system is configured to irradiate a laser beam focused into a minute spot for exposure on a photoresist film of 1000 to 1500 angstroms thick formed on a glass disk serving as a substrate of the master disk, in a so-called bit-by-bit method to blink the beam in accordance with video or audio information. The irradiated disk is then developed to provide a series of pits (recesses), wherein information is recorded in the form of the length of each pit and its repeating interval.
In the optical disk mastering process described above, since the surface of a photoresist master disk is traced by one or several laser beams to record information while the disk is rotating, the entire track length must be traced continuously. This, however, takes a long time. Additionally, since a laser beam is used to expose the photoresist layer of the master disk, it is difficult to provide a very minute beam spot because of the optical limitation. For these reasons, higher recording density cannot easily be achieved with the conventional photoresist master disk.